The general pokemon games seemed to be too easy for me. In fact, I kind of wished pokemon games had an Easy or Hard mode, similar to Golden Sun. Grinding just wasn't really needed in those games, at least for me. With Reborn its a lot different due to its difficulty. That's why I enjoy reborn. Sure I don't like grinding from lvl 1 to 50, but knowing the satisfaction of the end result is enough for me.
Also, I agree with Ame on the whole difficulty of other ROM hacks. Dark Rising gave me nightmares...